This project will examine multiple environmental agents and inherited traits in baboons for interactions with one another and for their effects on cholesterol induced atherosclerosis. The experimental period will extend from birth to sexual maturity. The initial experiment will determine the effects of infant nutrition (breast vs formula) on serum lipids, cholesterol metabolism, and the long term reaction of the animal to dietary cholesterol and type of fat. Cholesterol absorption and turnover will be measured. Behavioral characteristics will be assessed by the signal count technique, and physical activity will be computed from activity records. The resulting data on each animal will be analyzed for effects of age, sex, infant diet, dietary cholesterol, type of dietary fat, behavior, and physical activity on serum lipids and on atherosclerosis. In a second phase, the heritability of selected characteristics will be computed and selective matings will be designed to test heritability and to enhance and reduce heritable characteristics (such as response to cholesterol challenge) that are thought to be associated with atherosclerosis. Through observations on the baboons similar to those in the initial phase, the mechanism by which the inherited trait produces its effect on atherosclerosis will be examined. In the third major experiment, the effects of cigarette smoke inhalation on cholesterol-induced atherosclerosis and on pulmonary function and structure will be determined with a cigarette smoking baboon model system in which baboons puff on cigarettes as a result of operant conditioning. BIBLIOGRAPHIC REFERENCES: Experimental atherosclerosis in the baboon. Henry C. McGill, Jr., Glen E. Mott, and Claud A. Bramblett. Primates in Medicine 9:41-65, 1976. Neutral steroid losses and cholesterol absorption in gnotobiotic baboons. Glen E. Mott, Cathy J. Roberts, Jorg W. Eichberg, Henry C. McGill, Jr., and S.S. Kalter. Experimental and Molecular Pathology, June, 1976, in press.